CN105005056B - A kind of spaceborne Assisted GPS method and system based on dynamics Orbit extrapolation - Google Patents
A kind of spaceborne Assisted GPS method and system based on dynamics Orbit extrapolation Download PDFInfo
- Publication number
- CN105005056B CN105005056B CN201510443835.9A CN201510443835A CN105005056B CN 105005056 B CN105005056 B CN 105005056B CN 201510443835 A CN201510443835 A CN 201510443835A CN 105005056 B CN105005056 B CN 105005056B
- Authority
- CN
- China
- Prior art keywords
- gps
- satellite
- leo
- gps satellite
- receiver
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/13—Receivers
- G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
- G01S19/28—Satellite selection
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/13—Receivers
- G01S19/34—Power consumption
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Position Fixing By Use Of Radio Waves (AREA)
Abstract
A kind of spaceborne Assisted GPS method based on dynamics Orbit extrapolation includes：1) orbital position extrapolation is carried out according to LEO-based GPS receiver the last time positioning result under low orbit satellite kinetic model and J2000.0 coordinate systems, obtains the outer push position of LEO-based GPS receiver and be transformed into ECEF coordinate systems；2) position for obtaining all gps satellites under ECEF coordinate systems is calculated according to effective GPS almanacs；3) angle of pitch of the same moment epoch all gps satellites to LEO-based GPS receiver is calculated, judge whether each gps satellite is visible to LEO-based GPS receiver, and all gps satellites are ranked up according to observability probability, obtain collated gps satellite PRN lists；4) gps satellite is carried out according to capture passage of the gps satellite PRN lists to LEO-based GPS receiver preferentially to configure.The present invention reduces the acquisition search number of LEO-based GPS receiver, improve locating speed.
Description
Technical field
The present invention relates to satellite navigation positioning technical field, more particularly to it is a kind of based on the spaceborne auxiliary of dynamics Orbit extrapolation
Help GPS method and system.
Background technology
LEO-based GPS receiver, it is necessary to all gps satellites (being 32 at present) progress acquisition search, obtains in positioning
It can be seen that the PRN (Pseudo Random Noise code, Pseudo-Random Noise Code) number of gps satellite；It is preferable to wherein signal quality
Visible gps satellite be tracked, carry out positioning calculations based at least 4 gps satellite signals.In the case of no auxiliary,
LEO-based GPS receiver acquisition module generally use captures, obtaining can to all gps satellites successively similar to the method for poll
See gps satellite；This needs to spend the more acquisition search time (taking around a few minutes clock time to 32 gps satellite captures),
Cause locating speed very slow.
Many area navigation positioning terminals (smart mobile phone, vehicle GPS etc.) pass through AGPS (Assisted Global
Positioning System, auxiliary global satellite positioning system) location technology solves above mentioned problem.Ground AGPS technology knot
GPS location and the advantage of mobile base station positioning have been closed, by the data-transformation facility of mobile network, very high positioning can be reached
Precision and locating speed quickly.Ground AGPS technology finds the basic flow of available gps satellite from positioning starting to GPS
Journey mainly includes：Equipment gets the cellular cell position being currently located from mobile base station；Equipment will be current by mobile network
The cellular cell position at place sends the AGPS location servers in network to；AGPS location servers are according to current area position
The currently available satellite information in the region (including the relevant information such as the frequency range of satellite, azimuth, angle of pitch) is inquired about, and is returned to
Equipment；GPS, can be with the currently available gps satellite of fast Acquisition according to obtained usable satellite information.So far, GPS connects
Receipts machine can normally receive gps signal, and GPS initialization procedures terminate.But LEO-based GPS operation of receiver is in hundreds of kms
On the satellite orbit of even more high, mobile base station and mobile network can not be utilized.Therefore, the AGPS technology on ground can not answer
For LEO-based GPS receiver, searching times are more, locating speed is still that LEO-based GPS receiver needs the big problem that solves slowly.
LEO-based GPS receiver is compared with ground GPS receiver, mainly with following different characteristics：
First, the visible gps satellite distribution of LEO-based GPS receiver covers with low orbit satellite orbit altitude and gps satellite antenna
Angle is relevant：With the increase of orbit altitude, on the one hand, above water visible gps satellite number is reduced, on the other hand, because of the earth
The celestial sphere conical section blocked, which reduces, causes the negative gps satellite number increase for receiving the elevation angle.Generally, LEO-based GPS receiver is visible
Gps satellite number is reduced with increasing for satellite orbit, it means that can to find at least 4 on higher low rail track
See that gps satellite needs more searching times, more capture times；
2nd, low orbit satellite is in high-speed motion state, and the switching of visible gps satellite is very fast in the LEO-based GPS receiver visual field,
It is easier that positioning losing lock occurs than ground GPS receiver.Interrupted if of short duration positioning occurs for receiver, visible GPS in the visual field
Satellite distribution changes greatly, and the last positioning result preserved in receiver can not be used directly to the current visible gps satellite of prediction,
It can only be repositioned with cold start mode.Therefore, LEO-based GPS receiver is less there is thermal starting, startup temperature, essentially cold to open
It is dynamic；
3rd, LEO-based GPS receiver has strict requirements in design to the power consumption of entirety, is not influenceing the premise of positioning
Under, power consumption caused by receiver is more few better.To save power supply power consumption, LEO-based GPS receiver is knocked off between being often designed as
Operation mode, in order to carry out other load tasks.For example the CanX-2 satellites of Canada's transmitting, its LEO-based GPS receiver are continuous
Working time is no more than 50 minutes；The BIRD Nano satellites of Germany consider power consumption limit, when spaceborne infrared camera is opened, GPS
Receiver can only be closed；The LEO-based GPS receiver of the PCsat satellites in the U.S. must in most cases shut down, in order to
In-orbit communication remote sensing system can work, and under regular situation, the LEO-based GPS receiver maximum continuous working period is no more than 9 points
Clock.
Due to the above feature of LEO-based GPS receiver, the reduction acquisition search time turns into LEO-based GPS receiver one
Individual urgent problem to be solved.How simple, effective, quick, high accuracy, R ＆ D Cost low LEO-based GPS receiver acquisition is designed
Accessory system, solve to take problem existing for blind search method, improve the dynamic property and fast positioning ability of navigation positioning system,
In limited boot running time, gps position measurement as much as possible is carried out, is the new skill of LEO-based GPS receiver design
Art challenge.
The content of the invention
It is an object of the present invention to for LEO-based GPS receiver acquisition searching times in the prior art are more, the time compared with
Technical problem long, locating speed is slower, there is provided a kind of spaceborne Assisted GPS method and system based on dynamics Orbit extrapolation,
Using low orbit satellite track motion rule as auxiliary information, realize and reduce the acquisition search number of LEO-based GPS receiver, improve positioning
Speed.
To achieve the above object, the invention provides a kind of spaceborne Assisted GPS method based on dynamics Orbit extrapolation, bag
Include following steps：(1) it is the last fixed according to LEO-based GPS receiver under low orbit satellite kinetic model and J2000.0 coordinate systems
Position result carries out orbital position extrapolation, obtains the outer push position of LEO-based GPS receiver and is transformed into ECEF coordinate systems；(2) basis
Effective GPS almanacs calculate the position for obtaining all gps satellites under ECEF coordinate systems；(3) same moment epoch all GPS are calculated to defend
Star judges whether each gps satellite is visible to LEO-based GPS receiver to the angle of pitch of LEO-based GPS receiver, and according to observability
Probability is ranked up to all gps satellites, obtains collated gps satellite PRN lists；(4) according to the gps satellite PRN
The capture passage of number list to LEO-based GPS receiver carries out gps satellite and preferentially configured.
To achieve the above object, present invention also offers a kind of spaceborne assisted GPS sys based on dynamics Orbit extrapolation,
Including：Dynamics Orbit extrapolation module, gps satellite position computation module, visible gps satellite computing module and capture passage are matched somebody with somebody
Put module；The dynamics Orbit extrapolation module, for according to spaceborne under low orbit satellite kinetic model and J2000.0 coordinate systems
GPS the last time positioning result carries out orbital position extrapolation, obtains the outer push position of LEO-based GPS receiver and is transformed into
ECEF coordinate systems；The gps satellite position computation module, institute under ECEF coordinate systems is obtained for being calculated according to effective GPS almanacs
There is the position of gps satellite；The visible gps satellite computing module is defended with the dynamics Orbit extrapolation module and GPS respectively
Star position computation module is connected, and for calculating same moment epoch all gps satellites to the angle of pitch of LEO-based GPS receiver, sentences
Whether each gps satellite that breaks is visible to LEO-based GPS receiver, and all gps satellites are ranked up according to observability probability, obtains
Take collated gps satellite PRN lists；The capture passage configuration module is connected with the visible gps satellite computing module,
Preferentially configured for carrying out visible gps satellite according to capture passage of the gps satellite PRN lists to LEO-based GPS receiver.
The advantage of the invention is that：
1), by predicting the visible gps satellite in a period of time, the preferential gps satellite that will be seen that probability is big is allocated to star
The capture passage of GPS is carried, the acquisition and tracking of visible gps satellite in the visual field is switched in real time, it is possible to reduce is received
Machine acquisition search number, positioning time is efficiently reduced, can especially greatly shorten the head of LEO-based GPS receiver under cold start mode
Secondary positioning time and the search time compared with GPS on height rail satellite orbit；
2), when calculating visible gps satellite, the characteristics of taking into full account spaceborne environment, according to low orbit satellite orbit altitude and
Gps satellite antenna footprint, the visible gps satellite criterion for being adapted to LEO-based GPS receiver is proposed, compared to ground receiver depending on bowing
Gps satellite of the elevation angle more than 5 degree or 10 degree is visible, and the present invention can be predicted more effectively in the LEO-based GPS receiver visual field exactly
Visible gps satellite；
3), the calculating of the angle of pitch cannot be only used for judging visible gps satellite.When visible gps satellite number is more in the visual field
When, the preferably visible gps satellite of geometry distribution is simply chosen according to the angle of pitch and azimuth and combined, receiver can be improved
Positioning precision；Except the angle of pitch is that the angle of pitch can use for negative gps satellite in addition to positive gps satellite is used for location Calculation, track determination
In LEO occultation, suitable for the satellite of the measurement task over the ground such as atmospheric retrieval；
4), because the cold start-up time shortens, receiver can be closed when not needing LEO-based GPS operation of receiver；When needing GPS
During positioning, receiver, fast quick-recovery GPS location, the overall power of reduction LEO-based GPS receiver are opened；
5) system design and function, are realized in a software form, it is not necessary to extra hardware design, save development cost, contracting
The short design cycle, simplify debugging efforts.
Brief description of the drawings
Fig. 1, the flow chart of the spaceborne Assisted GPS method of the present invention based on dynamics Orbit extrapolation；
Fig. 2, the capture passage configuration flow schematic diagram of LEO-based GPS receiver of the present invention；
Fig. 3, the configuration diagram of the spaceborne assisted GPS sys of the present invention based on dynamics Orbit extrapolation；
Fig. 4, the handling process of spaceborne Assisted GPS method one embodiment of the present invention based on dynamics Orbit extrapolation
Figure；
Fig. 5, single gps satellite cover feature schematic diagram to the space of LEO-based GPS receiver；
Fig. 6, capture the average search number simulation result schematic diagram needed for 4 visible gps satellites；
Fig. 7, capture the average search number simulation result schematic diagram needed for 6 visible gps satellites.
Embodiment
Spaceborne Assisted GPS method and system provided by the invention based on dynamics Orbit extrapolation are done below in conjunction with the accompanying drawings
Describe in detail.
With reference to figure 1, the flow chart of the spaceborne Assisted GPS method of the present invention based on dynamics Orbit extrapolation is described
Method comprises the following steps：S11：It is nearest according to LEO-based GPS receiver under low orbit satellite kinetic model and J2000.0 coordinate systems
One-time positioning result carries out orbital position extrapolation, obtains the outer push position of LEO-based GPS receiver and is transformed into ECEF coordinate systems；
S12：The position for obtaining all gps satellites under ECEF coordinate systems is calculated according to effective GPS almanacs；S13：Calculate same moment epoch
All gps satellites judge whether each gps satellite is visible to LEO-based GPS receiver to the angle of pitch of LEO-based GPS receiver, and
All gps satellites are ranked up according to observability probability, obtain collated gps satellite PRN lists；S14：According to described
Capture passage of the gps satellite PRN lists to LEO-based GPS receiver carries out visible gps satellite and preferentially configured；Below in conjunction with accompanying drawing
Provide and explain in detail.
S11：According to the last positioning of LEO-based GPS receiver under low orbit satellite kinetic model and J2000.0 coordinate systems
As a result orbital position extrapolation is carried out, the outer push position of LEO-based GPS receiver is obtained and is transformed into ECEF coordinate systems.
Step S11 be specifically as follows including：Obtain LEO-based GPS receiver the last time positioning result and reception to be predicted
The machine time, and judging the receiver time to be predicted with the time interval of the last positioning result in effective power
When in time interval of extrapolating, orbital position extrapolation is carried out by starting of the last positioning result, LEO-based GPS is obtained and receives
Position coordinates is simultaneously converted into ECEF coordinate systems by the outer push position of machine from J2000.0 coordinate systems.If during receiver to be predicted
Between exceeded effective power as defined in system with the time interval of the last positioning result and extrapolated time interval, then dynamics
Extrapolation error is by beyond the error tolerance of system, and now spaceborne assistant GPS (i.e. AGPS) method calculation error is larger, so
AGPS calculating is not performed.
S12：The position for obtaining all gps satellites under ECEF coordinate systems is calculated according to effective GPS almanacs.
Step S12 is specifically as follows：Obtain the reference time of effective GPS almanacs and receiver time to be predicted, and
Judge that when the GPS almanacs were calculated in effective time, institute is calculated according to the GPS almanacs for the receiver time to be predicted
There is the position and speed of gps satellite, obtain the position of all gps satellites under ECEF coordinate systems.If receiver time to be predicted
Calculate effective time beyond GPS almanacs as defined in system, GPS almanacs calculation error by beyond the error tolerance of system,
Now AGPS methods calculation error is larger, so AGPS calculating is not performed.
S13：The angle of pitch of the same moment epoch all gps satellites to LEO-based GPS receiver is calculated, judges that every GPS is defended
Whether star is visible to LEO-based GPS receiver, and all gps satellites are ranked up according to observability probability, obtains collated
Gps satellite PRN lists.
Step S13 is specifically as follows：1) according to each gps satellite position at same moment epoch and LEO-based GPS receiver
Position calculates the angle of pitch and azimuth of each gps satellite to LEO-based GPS receiver, and the span of the wherein angle of pitch is ± 90
Degree；2) orbit altitude of low orbit satellite judges each gps satellite to spaceborne according to where each angle of pitch and LEO-based GPS receiver
Whether GPS is visible；3) all gps satellites are ranked up according to observability probability and obtain collated gps satellite PRN
Number list.
As optional embodiment, it is described according to observability probability to all gps satellites be ranked up obtain it is collated
Gps satellite PRN lists can be：Visible gps satellite is predicted as prior to invisible gps satellite；Be predicted as it is visible
Gps satellite in, the gps satellite near from overlay area central point is prior to the gps satellite remote from overlay area central point；Pre-
Survey as in sightless gps satellite, the gps satellite near from coverage area boundaries point is prior to remote from coverage area boundaries point
Gps satellite.
S14：Visible gps satellite is carried out according to capture passage of the gps satellite PRN lists to LEO-based GPS receiver
Configuration.
Step S14 is specifically as follows：1) gps satellite PRN list of the current time by sequence is obtained；2) judge visible
Whether gps satellite number is more than predetermined number threshold value, if performing step 3) less than if, otherwise performs step 4)；3) according to
Gps satellite PRN lists will be seen that the capture passage that gps satellite PRN is allocated to LEO-based GPS receiver；4) according to visible GPS
The angle of pitch of satellite and the corresponding visible gps satellite combination of azimuth selection, are allocated to LEO-based GPS by selected gps satellite PRN and connect
The capture passage of receipts machine.Configuration flow is referred to shown in Fig. 2.As optional embodiment, the visible gps satellite combination
Selection further for：Select one to two angle of pitch closest according to the configurable capture channel number of LEO-based GPS receiver first
Positive 90 degree of the visible gps satellite of zenith；The selection angle of pitch is just, uniformly more GPS defends closest to 0 degree and azimuthal distribution
Star, visible gps satellite combination is formed afterwards.Now, the GDOP (Geometric of selected visible gps satellite combination
Dilution of Precision, geometric dilution of precision, be one of the major criterion for weighing a Locating System Accuracy) value compared with
It is small, it is favorably improved receiver positioning precision.That is, when visible satellite number is more, can be according to the angle of pitch and azimuth
The preferably visible gps satellite combination of geometry distribution is selected, the capture passage to receiver configures, and obtains preferable positioning accurate
Degree.
With reference to figure 3, the configuration diagram of the spaceborne assisted GPS sys of the present invention based on dynamics Orbit extrapolation,
The spaceborne assisted GPS sys (i.e. AGPS systems) include dynamics Orbit extrapolation module 31, gps satellite position computation module
32nd, visible gps satellite computing module 33 and capture passage configuration module 34.Wherein, LEO-based GPS receiver 39 is using traditional
GPS, Fig. 3 are also shown for it and form framework substantially, including：Antenna 391, radio frequency part 392, trapping module 393, tracking
Module 394, position, frame synchronization 395 and PVT resolve module 396.
The dynamics Orbit extrapolation module 31, for according under low orbit satellite kinetic model and J2000.0 coordinate systems
39 the last positioning result of LEO-based GPS receiver carries out orbital position extrapolation, obtains the outer push position of LEO-based GPS receiver 39
And it is transformed into ECEF coordinate systems.The working method of the dynamics Orbit extrapolation module 31 can be：Obtain LEO-based GPS receiver
39 the last (i.e. last) positioning results and receiver time to be predicted, and in the judgement receiver to be predicted
Between with the time interval of the last positioning result in effective power extrapolation time interval when, the last positioned with described
As a result orbital position extrapolation is carried out for starting, obtains the outer push position of LEO-based GPS receiver 39 and by position coordinates from J2000.0
Coordinate system is converted into ECEF coordinate systems.If time interval has exceeded effective power extrapolation time interval as defined in system,
Dynamics extrapolation error by beyond the error tolerance of system, now spaceborne assistant GPS (i.e. AGPS) method calculation error compared with
Greatly, so not performing AGPS calculating.
The gps satellite position computation module 32, own for being calculated to obtain under ECEF coordinate systems according to effective GPS almanacs
The position of gps satellite.The working method of the gps satellite position computation module 32 can be：Obtain the reference of effective GPS almanacs
Time and receiver time to be predicted, and judging that the receiver time to be predicted is effective in GPS almanacs calculating
When in the time, the position and speed of all gps satellites is calculated according to the GPS almanacs, obtains all gps satellites under ECEF coordinate systems
Position.If receiver time to be predicted calculates effective time beyond GPS almanacs as defined in system, GPS almanacs calculate
For error by beyond the error tolerance of system, now AGPS methods calculation error is larger, is calculated so not performing AGPS.
The visible gps satellite computing module 33 respectively with the dynamics Orbit extrapolation module 31 and gps satellite position
Put computing module 32 to be connected, for calculating same moment epoch all gps satellites to the angle of pitch of LEO-based GPS receiver 39, sentence
Whether each gps satellite that breaks is visible to LEO-based GPS receiver, and all gps satellites are ranked up according to observability probability, obtains
Take collated gps satellite PRN lists.The working method of the visible step of gps satellite computing module 33 can be：According to same
Each gps satellite position at one moment epoch and the position of LEO-based GPS receiver 39 calculate each gps satellite and LEO-based GPS are received
The span at the angle of pitch of machine 39 and azimuth, the wherein angle of pitch is ± 90 degree；Received according to each angle of pitch and LEO-based GPS
The orbit altitude of the place low orbit satellite of machine 39 judges whether each gps satellite is visible to LEO-based GPS receiver 39；According to observability
Probability is ranked up to all gps satellites and obtains collated gps satellite PRN lists.
The capture passage configuration module 34 is connected with the visible gps satellite computing module 33, and is received with LEO-based GPS
The trapping module 393 of machine 39 is connected, for according to capture passage of the gps satellite PRN lists to LEO-based GPS receiver 39
Carry out visible gps satellite configuration.The working method of the capture passage configuration module 34 can be：Current time GPS is obtained to defend
Star PRN lists；Judge whether visible gps satellite number is more than predetermined number threshold value, according to the gps satellite if being less than
PRN lists will be seen that the capture passage that gps satellite PRN is allocated to LEO-based GPS receiver；Otherwise according to visible gps satellite
The angle of pitch and the corresponding visible gps satellite of azimuth selection combine and selected gps satellite PRN be allocated to LEO-based GPS receiver
Capture passage.
With reference to figure 4, the processing stream of spaceborne Assisted GPS method one embodiment of the present invention based on dynamics Orbit extrapolation
Cheng Tu.In the present embodiment, the Base-Band Processing and positioning calculation process of LEO-based GPS receiver are realized in FPGA and DSP, spaceborne auxiliary
Help GPS to complete to calculate in dsp, and result is fed back to the trapping module in FPGA.With reference to shown in figure 4, obtain first
(PVT is the extrapolation of low orbit satellite dynamics to receiver the last time positioning result PVT under J2000.0 mean equator inertial coodinate systems
Starting point, 6 n dimensional vector ns being made up of position, speed are designated asDuring corresponding epoch
Engrave as t0)；And receiver time t to be predicted；According to t0Judge predicted time t whether in the extrapolation of effective dynamics with t
In interval, if exceeding, the error of dynamics extrapolation is larger, and the visible satellite error that AGPS methods are calculated is larger, so this
When without using AGPS methods；If without departing from effective power Orbit extrapolation time interval, according to GPS almanac reference times toaAnd t
Judge it is whether effective in t GPS almanacs, if almanac fail, the mistake for the gps satellite coordinate position being calculated according to almanac
Difference is larger so that and AGPS system-computed resultant errors are larger, so now without using AGPS methods；It is not super when the time of prediction
Go out effective dynamics extrapolation interval, also without departing from the effective time of GPS almanacs when, perform successively follow-up in AGPS systems
Step：Dynamics Orbit extrapolation and GPS location calculate, calculate visible gps satellite, the capture passage of configuration LEO-based GPS receiver.
In the present embodiment, the Orbit extrapolation position of low orbit satellite, integration are calculated using RK4 Runge-Kutta numerical integrations device
Device step-length takes 30s.The general type of classical RK4 methods is：
Wherein, h is step-length, and Φ is increment of a function, and it passes through 4 slope (k1-k4) weighted average calculation obtain：
ΦRK4=1/6 (k1+2k2+2k3+k4)
Wherein
k1=f (t0,y0)
k2=f (t0+h/2,y0+hk1/2)
k3=f (t0+h/2,y0+hk2/2)
k4=f (t0+h,y0+hk3)
Above-mentioned formula is accurate to h4Magnitude, therefore the accuracy of RK4 methods is equivalent to quadravalence Taylor polynomial.
In the present embodiment, y in above-mentioned Numerical Integral Formulas0Corresponding LEO-based GPS receiver is in t0The coordinate vector at moment, f
(t0,y0) correspond to t0Moment coordinate vector is y0Low orbit satellite stress sum.In view of amount of calculation and computational accuracy, establish dynamic
Simplified perturbative force model is selected during mechanical model：JGM-03 gravity field models, the atmospheric drag of 70 × 70 ranks.Dynamics track
Extrapolation calculates in J2000.0 coordinate systems, and obtained extrapolating results are also the PVT under J2000.0 coordinates, and visible gps satellite
Computing module is calculated based on the PVT under ECEF coordinate systems, therefore is postponed outside dynamics, should be transformed into outer push position
In ECEF coordinate systems.
In the present embodiment, the orbital position of all gps satellites is calculated according to effective GPS almanacs.Although according to outside ephemeris
More accurate coordinate position can be obtained by pushing away, but too short, it is necessary to frequent updating GPS ephemeris in view of the term of validity of ephemeris, so
The coordinate position of gps satellite under ECEF ECEF coordinate systems is calculated using GPS almanacs.
In the present embodiment, according to the LEO-based GPS receiver coordinate and gps satellite under same moment epoch ECEF coordinate system
Coordinate, all gps satellites can be calculated each to the angle of pitch e of receiver, its span is [- 90 °, 90 °], is calculated public
Formula is：
Wherein,Refer to the vector of the earth's core beacon receiver,Refer to the vector that receiver points to gps satellite.
With reference to figure 5, single gps satellite covers feature schematic diagram to the space of LEO-based GPS receiver.As shown in figure 5, GPS
Satellite is different from ground GPS receiver to the covering feature of the LEO-based GPS receiver on low rail track, and LEO-based GPS receives
The visible gps satellite distribution of machine is relevant with low orbit satellite orbit altitude and gps satellite antenna cone of coverage：With the increasing of orbit altitude
Add, on the one hand above water visible gps satellite number is reduced, and on the other hand, is made because the celestial sphere conical section that the earth blocks reduces
The gps satellite number increase for receiving the angle of pitch must be born, generally, the visible gps satellite number of LEO-based GPS receiver is with satellite orbit
Increase and reduce.LEO-based GPS receiver can receive the gps signal of the negative angle of pitch, in addition to available for positioning, usually use
Tested in scientific observations such as LEO occultations.Ground receiver regards gps satellite of the angle of pitch more than 5 degree or 10 degree to be visible visible
Star decision method is not suitable for LEO-based GPS receiver.
According to space geometry relation, the visible gps satellite criterion being derived by suitable for LEO-based GPS receiver is：
Wherein,
α is gps antenna subtended angle, rGPSIt is the orbit radius of gps satellite, rearthIt is the mean equatorial radius of the earth, hleoIt is
Height of the low orbit satellite apart from earth surface.HleoCritical orbit height, i.e. circuit orbit orbit2 orbit altitude in Fig. 5,
Now the border of gps signal coverage is just tangent with critical orbit.eA、eBAnd eCThen represent on low rail track, certain moment is low
The angle of pitch on theoretical circular track where rail satellite at single visible gps satellite scope critical point.Work as hleo＜ HleoWhen, such as
Fig. 5 middle orbit orbit1, the signal between LEO-based GPS receiver and gps satellite are propagated and can only blocked by the earth, and the elevation angle meets eA
It is visible with to LEO-based GPS receiver that ＜ e≤90 ° are considered as the gps satellite；Work as hleo＞ HleoWhen, such as Fig. 5 middle orbit orbit3,
In addition to it can be blocked by the earth, also influenceed by the antenna footprint of gps satellite, the elevation angle meets eC＜ e≤90 °, e ＞ 0 or eA＜
E ＜ eB, think that the gps satellite is visible with to LEO-based GPS receiver during e ＜ 0.
It is given below it is of the present invention based on the spaceborne Assisted GPS method of dynamics Orbit extrapolation in STK softwares and
Emulation in MATLAB softwares.Visible relation of the gps satellite to low orbit satellite is exported in STK, as reference point, for performance pair
Than；And export the PVT of first emulation sampled point low orbit satellite, the starting as the extrapolation of MATLAB medium and low earth orbit satellites dynamics.
The calculating process of spaceborne assisted GPS sys is realized in MATLAB softwares：Gps satellite position calculates, low orbit satellite Orbit extrapolation
Predicted with visible star.
In emulation, GPS constellation is established according to true GPS almanacs in STK, the antenna angle of every gps satellite is arranged to
30 degree.Low orbit satellite orbit altitude changes to 2000km from 300km, and remaining orbit parameter is constant：Inclination angle is 30 degree, and eccentricity is
0, right ascension of ascending node 0, the argument of perigee 0, true anomaly 0.Duration is emulated on each track every time 24 hours.Consider
The almanac age used is longer, calculates the error that the error of gps satellite position is bigger, causes angle of pitch calculating, visible star to be predicted
It is bigger.The GPS almanacs of 26 week age (the almanac term of validity is half a year) are selected in MATLAB to predict the position of gps satellite,
The performance of spaceborne Assisted GPS method is verified in the case of maximum almanac calculation error.
In order to verify the performance advantage of spaceborne Assisted GPS method, in simulations by spaceborne assistant GPS side provided by the invention
Method is searched for existing poll and contrasted by track faceted search.Poll searching method refers to：According to PRN1~32 sequentially
Search for gps satellite；Refer to by orbital plane searching method：1 satellite in search track face A first, then search track face B
1 satellite, the rest may be inferred.During using spaceborne Assisted GPS method, acquisition search is carried out according to the PRN lists by sequence.
With reference to figure 6, illustrated using capturing simulation result of 4 visible gps satellites as the average search number needed for target
Figure.In simulations, the searching times needed for 4 visible gps satellites of record search, count in each low rail orbit altitude, it is every kind of
Search star method and search the searching times that 4 visible gps satellites averagely need.Understand as shown in Figure 6：Defended to search 4 GPS
Star, the capture number needed for these three methods all increase and increased with the orbit altitude of low orbit satellite.Because：With track
Increase, the visible gps satellite of LEO-based GPS receiver are reduced, and the number needed for 4 visible satellites is found in 32 gps satellites
Increase.Searched for compared to poll and by track faceted search, in all low rail orbit altitudes, what spaceborne Assisted GPS method needed
Searching times are minimum, and as orbit altitude increases, the increasing degree of its required searching times is the slowest.Work as low orbit satellite
Orbit altitude from 300km increase to 2000km when, the average search number needed for poll search increases to 22.19 from 9.03, increases
Width is violent；And spaceborne Assisted GPS method then increases to 9.67 from 4.19, amplification is gentle.Assuming that the search once to fail continues 40
Second, and once successfully search continues 20 seconds 24.So, when low orbit satellite orbit altitude is 300km high, capturing every time
In, poll search averagely needs 281.2 seconds, and spaceborne Assisted GPS method only needs 87.6 seconds, when reducing 68.85% capture
Between；When low orbit satellite orbit altitude is 2000km, in each capture, sequential search averagely needs 807.6 seconds, and spaceborne auxiliary
Help GPS method only to need 306.8 seconds, save 62.01% capture time.
With reference to figure 7, illustrated using capturing simulation result of 6 visible gps satellites as the average search number needed for target
Figure.When more visible gps satellites are used for positioning calculation, GPS can obtain more preferable positioning precision.Emulating
In, to capture 6 visible gps satellites as target, repeat above-mentioned emulation.Understand as shown in Figure 7：Defended to search 6 GPS
Star, the capture number needed for these three methods all increases and increased with the orbit altitude of low orbit satellite, and spaceborne Assisted GPS method
Required capture number is still considerably less than other two method.But comparison diagram 6 and Fig. 7 can see, when low orbit satellite track is high
When spending higher (being higher than 1000km), the searching times amplification searched for needed for 6 visible gps satellites is more violent, because low
Rail satellite orbital altitude is higher, and visible gps satellite is fewer in the LEO-based GPS receiver visual field, captures what 6 gps satellites needed
Searching times are more, even can not search 6 visible satellites sometimes.When low orbit satellite orbit altitude is 300km high, every
In secondary capture, poll search averagely needs 12.12 times, about 404.8 seconds, and spaceborne Assisted GPS method only needs 6.33 times, about
For 173.2 seconds, reduce 55% capture time；When low orbit satellite orbit altitude is 2000km, in each capture, poll
Search averagely needs 29.56 times, about 1102.4 seconds, and spaceborne Assisted GPS method only needs 23.47 times, about 858.8 seconds, section
22.10% capture time is saved.
Above-mentioned simulation result shows that, when low rail track relatively low (being less than 1000km), spaceborne Assisted GPS method can be quick
At least 6 gps satellites are captured, capture time is not only shortened, also contributes to positioning precision；When low rail track is higher
(being higher than 1000km), spaceborne Assisted GPS method still can shorten capture time with fast Acquisition to 4 gps satellites.
Spaceborne assistant GPS (AGPS) method and system proposed by the present invention based on low orbit satellite dynamics Orbit extrapolation,
Using the track operation characteristic of low orbit satellite as auxiliary information, according to covering feature of the gps satellite to low orbit satellite, real-time estimate
The visible gps satellite of LEO-based GPS receiver, star method is searched to substitute traditional poll, reduce the acquisition search of receiver
Number, especially shortens primary positioning time during cold start-up.Therefore can suitably increase LEO-based GPS receiver unused time and
Shut down number, saves low orbit satellite overall power.In the track-bound that can not carry out GPS location, outside low orbit satellite dynamics
The orbital position of low orbit satellite can be predicted by pushing away, until low orbit satellite move to can GPS location region, during with shorter cold start-up
Between fast quick-recovery positioning, and carry out orbital exponent.Therefore, this method allows the application of LEO-based GPS receiver to expand
Open up higher track.And the present invention can realize system design and function in a software form, it is not necessary to extra hardware design,
Development cost is saved, shortens the design cycle, simplifies debugging efforts.
Described above is only the preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
Member, under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications also should be regarded as
Protection scope of the present invention.
Claims (8)
1. a kind of spaceborne Assisted GPS method based on dynamics Orbit extrapolation, it is characterised in that comprise the following steps：
(1) entered according to LEO-based GPS receiver the last time positioning result under low orbit satellite kinetic model and J2000.0 coordinate systems
Row orbital position is extrapolated, and is obtained the outer push position of LEO-based GPS receiver and is transformed into ECEF coordinate systems；
(2) position for obtaining all gps satellites under ECEF coordinate systems is calculated according to effective GPS almanacs；
(3) same moment epoch all gps satellites are calculated to the angle of pitch of LEO-based GPS receiver, judge each gps satellite to star
Whether visible carry GPS, and all gps satellites are ranked up according to observability probability, obtain collated gps satellite
PRN lists；
(4) gps satellite is carried out according to capture passage of the gps satellite PRN lists to LEO-based GPS receiver preferentially to configure.
2. spaceborne Assisted GPS method according to claim 1, it is characterised in that step (1) further comprises：Obtain star
Carry GPS the last time positioning result and receiver time to be predicted, and when judging the receiver to be predicted
Between with the time interval of the last positioning result in effective power extrapolation time interval when, the last positioned with described
As a result orbital position extrapolation is carried out for starting.
3. spaceborne Assisted GPS method according to claim 1, it is characterised in that step (2) further comprises：Acquisition has
The reference time of GPS almanacs and receiver time to be predicted are imitated, and is judging the receiver time to be predicted described
When GPS almanacs were calculated in effective time, the position and speed of all gps satellites is calculated according to the GPS almanacs, obtains ECEF coordinates
The position of all gps satellites under system.
4. spaceborne Assisted GPS method according to claim 1, it is characterised in that step (3) further comprises：
(31) each gps satellite pair is calculated according to each gps satellite position at same moment epoch and LEO-based GPS receiver location
The span at the angle of pitch of LEO-based GPS receiver and azimuth, the wherein angle of pitch is ± 90 degree；
(32) orbit altitude of low orbit satellite judges each gps satellite pair according to where each angle of pitch and LEO-based GPS receiver
Whether LEO-based GPS receiver is visible；
(33) all gps satellites are ranked up according to observability probability and obtain collated gps satellite PRN lists.
5. spaceborne Assisted GPS method according to claim 4, it is characterised in that it is described according to observability probability to all
Gps satellite be ranked up obtain collated gps satellite PRN lists be further：It is preferential to be predicted as visible gps satellite
In invisible gps satellite；In visible gps satellite is predicted as, the gps satellite near from overlay area central point is prior to from covering
The remote gps satellite of cover area central point；In sightless gps satellite is predicted as, the gps satellite near from coverage area boundaries point
Prior to the gps satellite remote from coverage area boundaries point.
6. spaceborne Assisted GPS method according to claim 1, it is characterised in that step (4) further comprises：
(41) current time collated gps satellite PRN lists are obtained；
(42) judge whether visible gps satellite number is more than predetermined number threshold value, if performing step (43) less than if, otherwise perform
Step (44)；
(43) it will be seen that No. PRN capture for being allocated to LEO-based GPS receiver of gps satellite is led to according to the gps satellite PRN lists
Road；
(44) corresponding visible gps satellite is selected to combine according to the angle of pitch of visible gps satellite and azimuth, by selected gps satellite
No. PRN capture passage for being allocated to LEO-based GPS receiver.
7. spaceborne Assisted GPS method according to claim 6, it is characterised in that the selection of the visible gps satellite combination
It is further：
(441) one to two angle of pitch is selected closest to positive 90 degree according to the configurable capture channel number of LEO-based GPS receiver
The visible gps satellite of zenith；
(442) select the angle of pitch for just, closest to the uniform more visible gps satellites of 0 degree and azimuthal distribution；
(443) visible gps satellite combination is formed.
A kind of 8. spaceborne assisted GPS sys based on dynamics Orbit extrapolation, it is characterised in that including：Dynamics Orbit extrapolation
Module, gps satellite position computation module, visible gps satellite computing module and capture passage configuration module；
The dynamics Orbit extrapolation module, for according to LEO-based GPS under low orbit satellite kinetic model and J2000.0 coordinate systems
Receiver the last time positioning result carries out orbital position extrapolation, obtains the outer push position of LEO-based GPS receiver and is transformed into
ECEF coordinate systems；
The gps satellite position computation module, defended for calculating all GPS under acquisition ECEF coordinate systems according to effective GPS almanacs
The position of star；
The visible gps satellite computing module calculates mould with the dynamics Orbit extrapolation module and gps satellite position respectively
Block is connected, and for calculating same moment epoch all gps satellites to the angle of pitch of LEO-based GPS receiver, judges each gps satellite
It is whether visible to LEO-based GPS receiver, and all gps satellites are ranked up according to observability probability, obtain collated GPS
Satellite PRN lists；
The capture passage configuration module is connected with the visible gps satellite computing module, for according to the gps satellite PRN
The capture passage of number list to LEO-based GPS receiver carries out gps satellite and preferentially configured.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510443835.9A CN105005056B (en) | 2015-07-24 | 2015-07-24 | A kind of spaceborne Assisted GPS method and system based on dynamics Orbit extrapolation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510443835.9A CN105005056B (en) | 2015-07-24 | 2015-07-24 | A kind of spaceborne Assisted GPS method and system based on dynamics Orbit extrapolation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105005056A CN105005056A (en) | 2015-10-28 |
| CN105005056B true CN105005056B (en) | 2017-12-05 |
Family
ID=54377790
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510443835.9A Expired - Fee Related CN105005056B (en) | 2015-07-24 | 2015-07-24 | A kind of spaceborne Assisted GPS method and system based on dynamics Orbit extrapolation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105005056B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107783161A (en) * | 2016-08-30 | 2018-03-09 | 厦门雅迅网络股份有限公司 | A kind of method and system that GPS location effect is lifted using AGPS |
| CN106680843B (en) * | 2016-12-12 | 2019-10-25 | 大唐半导体设计有限公司 | A kind of receiver and the method for realizing receiver starting |
| CN109270558B (en) * | 2018-09-30 | 2021-04-13 | 中国气象局气象探测中心 | Shelter forecasting method for mountain base |
| CN109059916B (en) * | 2018-09-30 | 2021-05-18 | 中国气象局气象探测中心 | Aerostat occultation forecasting method based on inertial navigation |
| CN109639337B (en) * | 2018-11-23 | 2020-10-02 | 南京控维通信科技有限公司 | Graphic auxiliary satellite alignment method suitable for satellite communication equipment |
| CN109639341B (en) * | 2018-12-17 | 2021-01-01 | 西南电子技术研究所（中国电子科技集团公司第十研究所） | Method for autonomously accessing low-orbit broadcast satellite without ephemeris |
| CN110060552B (en) * | 2019-03-26 | 2021-07-20 | 南京航空航天大学 | Satellite constellation orbit physical simulation experiment platform |
| CN110816896B (en) * | 2019-10-28 | 2021-06-11 | 中国空间技术研究院 | Satellite on-satellite simple orbit extrapolation method |
| CN111948679B (en) * | 2020-08-12 | 2024-03-15 | Oppo广东移动通信有限公司 | Satellite searching method, device and computer readable storage medium |
| CN116931026B (en) * | 2023-09-15 | 2023-12-12 | 北京神导科技股份有限公司 | Abnormality determination method for satellite navigation signals |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2916279B1 (en) * | 2007-05-18 | 2009-08-07 | Astrium Sas Soc Par Actions Si | SATELLITE POSITIONING METHOD AND SYSTEM. |
| CN103064092B (en) * | 2012-12-28 | 2014-05-21 | 中国科学院光电研究院 | Selection method of navigational satellite |
| CN103823224B (en) * | 2014-03-04 | 2016-04-06 | 南京航空航天大学 | A kind of point rail satellite selection method based on Beidou satellite navigation system |
| CN104459731B (en) * | 2014-11-27 | 2017-01-04 | 上海交通大学 | A kind of high rail Satellite Orbit Determination method of the weak GNSS signal of receiving pole |
-
2015
- 2015-07-24 CN CN201510443835.9A patent/CN105005056B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN105005056A (en) | 2015-10-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105005056B (en) | A kind of spaceborne Assisted GPS method and system based on dynamics Orbit extrapolation | |
| US7817087B2 (en) | Method and apparatus for relative navigation using reflected GPS signals | |
| EP2488827B1 (en) | System and method for compensating for faulty measurements | |
| CN107678045B (en) | Global positioning system starting method, user terminal and related medium product | |
| CN101995579B (en) | Method and device for using global navigation satellite system (gnss) satellite trajectory extension data | |
| Silva et al. | Weak GNSS signal navigation to the moon | |
| CN112104411A (en) | Low-orbit satellite communication-oriented access satellite selection device and method | |
| Capuano et al. | High accuracy GNSS based navigation in GEO | |
| CN109061689B (en) | Satellite-borne GNSS receiver signal synchronization method based on orbital dynamics assistance | |
| Jiang et al. | LEO Doppler-aided GNSS position estimation | |
| CN109991631A (en) | Satellite positioning method and device, computer readable storage medium | |
| JP2009535605A (en) | Method and apparatus for performing code space search at receiver | |
| US20110050496A1 (en) | Energy Domain Based Peak Reconstruction Methods And Apparatuses | |
| Kovář | piNAV L1—GPS receiver for small satellites | |
| CN110300902A (en) | Support the extension of the validity period for the parameter value being defined to track | |
| CN102246056A (en) | Satellite positioning system signal searching methods and apparatuses | |
| US9877157B2 (en) | Autonomous in-device GNSS augmentation system | |
| WO2014020818A1 (en) | Position calculation method and position calculator | |
| Bamford et al. | A GPS receiver for lunar missions | |
| Unwin et al. | GNSS enabling new capabilities in space on the TechDemoSat-1 satellite | |
| Park et al. | Development of a GPS/INS system for precision GPS guided bombs | |
| CN106154300A (en) | A kind of hypercompact combination implementing method of inertia/satellite | |
| Ramanathan et al. | Investigation and Analysis into Establishing a Cislunar PNT System and Performing a Soft Landing on the Lunar Surface | |
| JP2008180598A (en) | Device for positioning mobile body | |
| Yang et al. | Assisted cold start method for GPS receiver with artificial neural network-based satellite orbit prediction |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20171205 Termination date: 20190724 |